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Re: [PATCH] [BZ #18970]: Reference of pthread_setcancelstate in libc.a
- From: "H.J. Lu" <hjl dot tools at gmail dot com>
- To: Joseph Myers <joseph at codesourcery dot com>
- Cc: Roland McGrath <roland at hack dot frob dot com>, GNU C Library <libc-alpha at sourceware dot org>
- Date: Thu, 17 Sep 2015 15:31:59 -0700
- Subject: Re: [PATCH] [BZ #18970]: Reference of pthread_setcancelstate in libc.a
- Authentication-results: sourceware.org; auth=none
- References: <20150917152135 dot GA25716 at intel dot com> <20150917195803 dot E05DF2C3B40 at topped-with-meat dot com> <CAMe9rOrGYk6s94vvSVC1R7uBS-qGZaH8Pdwr62G+ZZdgnLKeig at mail dot gmail dot com> <20150917215151 dot 6201A2C3B40 at topped-with-meat dot com> <alpine dot DEB dot 2 dot 10 dot 1509172152540 dot 2455 at digraph dot polyomino dot org dot uk>
On Thu, Sep 17, 2015 at 2:57 PM, Joseph Myers <joseph@codesourcery.com> wrote:
> On Thu, 17 Sep 2015, Roland McGrath wrote:
>
>> > Is this a valid test?
>>
>> No. There should be no need for individual tests like that. The
>> linknamespace tests should catch such things if the conform data is correct
>> (and if it's not, the right thing is to fix the conform data).
>
> See one of the caveats listed in linknamespace.pl:
>
> # * Weak undefined symbols are ignored; however, if a code path that
> # references one (even just to check if its address is 0) is executed,
> # that may conflict with a definition of that symbol in the user's
> # program.
>
> I don't know what combination of false positives and real problems you'd
> find if linknamespace.pl stopped special-casing weak symbols.
>
I think it is a mistake to use weak symbols for this purpose.
--
H.J.